When trying to use Julia's GR.jl library on Code Ocean you may encounter the following error:
GKS: can't open display on ""
Is your DISPLAY environment variable set correctly?
Did you enable X11 and TCP forwarding?
GKS: Open failed in routine OPEN_WS
On a headless system GR.jl needs to be configured with the output device, so make sure to set the environment variable in your
export GKSwstype=100 , or, if you'd like to set it in your Julia code,
using GR ,
For more information, see this GitHub issue.